Careful and precise articulation of elements in rotation, e.g. a shaft inside a bushing, is often essential for adjustable articulated systems, e.g. aircraft meal trays, adjustable seats, adjustable leg rests, adjustable armrest, bin doors, or the like. Such a demand for careful and precise articulation can be addressed with the ability to exert resistance and/or damping on the elements in rotation.
To this end, conventional apparatuses generating rotary resistance and/or providing torque reduction, e.g. rotary dampers, rotary hinge dampers, or the like, have been adopted. Usually, these conventional apparatuses rely on a viscous fluids encapsulated between a shaft in rotation and a sealed housing affixed to a bushing to generate resistance as the shaft is rotated.
Although such conventional apparatuses are widely used, they present important drawbacks. Notably, such conventional apparatuses lack of reliability as the viscous fluids may leak from the sealed housing or as physical properties of the viscous fluids can change and/or deteriorate rapidly due to temperature and/or pressure fluctuations as it is frequently experienced in aircraft applications. Furthermore, these conventional apparatuses do not provide adjustments, cycling, and/or incremental variations of the resistance exerted on the rotating elements which can be used to carefully and precisely articulate the elements in rotation.
Thus, an apparatus to provide resistance on rotating elements solving the problems of reliability, controllability, and adjustability is desired.